A novel ALK secondary mutation and EGFR signaling cause resistance to ALK kinase inhibitors

Frequency, clinical features and differential response to therapy of concurrent ALK/EGFR alterations in Chinese lung cancer patients

Purpose: EGFR and anaplastic lymphoma kinase (ALK) alterations have been regarded as oncogenic drivers and incorporated into clinical practices to manage nonsmall cell lung cancer (NSCLC). Alterations of these two genes were traditionally considered to be mutually exclusive, but recent studies have suggested that they can occur concomitantly. Here, we investigated the prevalence, clinical features and outcomes in response to the treatment of NSCLC patients who harbor EGFR and ALK co-alterations. Methods: We reviewed the genomic profiles of 419 ALK-rearranged NSCLC patients with the intent of investigating the EGFR kinase domain (exon 18-21) and ALK co-alterations. The genomes of these patients were sequenced in a Clinical Laboratory Improvement Amendments-certified laboratory. Results: The overall frequency of concomitant EGFR (exon 18-21) and ALK alterations was 5.01% (21/419) in ALK-rearranged NSCLC patients. The concomitant rate of EGFR alterations in patients with EML4-ALK co-alterations (3.06%, 11/359) was dramatically lower than that in patients with non-EML4-ALK co-alterations (16.67%, 10/60, p<0.01). EML4-ALK/EGF R co-alterations were more prone to occur in females than in males, and non-EML4-ALK/EGFR co-alterations were more common in males than in females (p=0.02). Before the detection of EGFR-ALK co-alterations, some patients were treated with EGFR-TKIs (n=16) according to previously detected EGFR alterations; Kaplan-Meier analysis revealed that EML4-ALK/EGFR co-altered patients (n=7) had a significantly shorter progression-free survival (PFS) after EGFR-TKI treatment than that of non-EML4-ALK/EGFR co-altered patients (n=8; mPFS, 6.0 vs 15.0 months, p=0.046). In addition, we demonstrated the subsequent clinical outcomes of co-altered patients after previous EGFR-TKI treatment. Five EGFR/ALK co-altered patients treated with single TKIs (EGFR-TKIs or ALK-TKIs) displayed diverse clinical outcomes. Three patients who received dual-TKI treatment (EGFR-TKI plus ALK-TKI) all achieved a PFS of more than 5 months (8.4 months, 8.6 months, >5.2 months). Conclusion: EML4-ALK/EGFR and non-EML4-ALK/EGFR co-alterations displayed distinct clinical features and responses to EGFR-TKIs, suggesting that non-EML4-ALK co-alterations are likely to occur as a resistance mechanism to EGFR-TKI. In addition, dual-TKI therapy might be a better choice than single-TKI treatments for these co-altered patients. To the best of our knowledge, this is the largest dual-positive EGFR/ALK cohort study in People's Republic of China.

Making the first move in EGFR-driven or ALK-driven NSCLC: first-generation or next-generation TKI?

The traditional approach to the treatment of patients with advanced-stage non-small-cell lung carcinoma (NSCLC) harbouring ALK rearrangements or EGFR mutations has been the sequential administration of therapies (sequential treatment approach), in which patients first receive first-generation tyrosine-kinase inhibitors (TKIs), which are eventually replaced by next-generation TKIs and/or chemotherapy upon disease progression, in a decision optionally guided by tumour molecular profiling. In the past few years, this strategy has been challenged by clinical evidence showing improved progression-free survival, improved intracranial disease control and a generally favourable toxicity profile when next-generation EGFR and ALK TKIs are used in the first-line setting. In this Review, we describe the existing preclinical and clinical evidence supporting both treatment strategies - the 'historical' sequential treatment strategy and the use of next-generation TKIs - as frontline therapies and discuss the suitability of both strategies for patients with EGFR-driven or ALK-driven NSCLC.

A Career in Lung Cancer: Pushing Beyond Chemotherapy

The landscape of treatments for non-small cell lung cancer (NSCLC) has evolved dramatically over the past 3 decades. A better understanding of the disease biology and identification of actionable genetic alterations heralded an era of targeted therapies that has led to unprecedented survival benefits in patients with oncogene-driven NSCLC. More recent breakthroughs in immunotherapy led to the development of immune checkpoint inhibitors that have changed the treatment paradigm for patients with advanced NSCLC because of their ability to produce durable responses, resulting in improved survival outcomes. Despite the unparalleled success of these agents, primary and acquired resistance to these therapies pose a formidable challenge. In this article, we provide an overview of the therapeutic advances in the treatment of NSCLC, mechanisms of resistance, and potential strategies to overcome resistance to targeted therapies and immune checkpoint inhibitors.

Identification of Genetic Mutations in Cancer: Challenge and Opportunity in the New Era of Targeted Therapy

The introduction of targeted therapy is the biggest success in the treatment of cancer in the past few decades. However, heterogeneous cancer is characterized by diverse molecular alterations as well as multiple clinical profiles. Specific genetic mutations in cancer therapy targets may increase drug sensitivity, or more frequently result in therapeutic resistance. In the past 3 years, several novel targeted therapies have been approved for cancer treatment, including drugs with new targets (i.e., anti-PD1/PDL1 therapies and CDK4/6 inhibitors), mutation targeting drugs (i.e., the EGFR T790M targeting osimertinib), drugs with multiple targets (i.e., the EGFR/HER2 dual inhibitor neratinib) and drug combinations (i.e., encorafenib/binimetinib and dabrafenib/trametinib). In this perspective, we focus on the most up-to-date knowledge of targeted therapy and describe how genetic mutations influence the sensitivity of targeted therapy, highlighting the challenges faced within this era of precision medicine. Moreover, the strategies that deal with mutation-driven resistance are further discussed. Advances in these areas would allow for more targeted and effective therapeutic options for cancer patients.

Receptor tyrosine kinases in PI3K signaling: The therapeutic targets in cancer

The phosphoinositide 3-kinase (PI3K) pathway, one of the most commonly activated signaling pathways in human cancers, plays a crucial role in the regulation of cell proliferation, differentiation, and survival. This pathway is usually activated by receptor tyrosine kinases (RTKs), whose constitutive and aberrant activation is via gain-of-function mutations, chromosomal rearrangement, gene amplification and autocrine. Blockage of PI3K pathway by targeted therapy on RTKs with tyrosine kinases inhibitors (TKIs) and monoclonal antibodies (mAbs) has achieved great progress in past decades; however, there still remain big challenges during their clinical application. In this review, we provide an overview about the most frequently encountered alterations in RTKs and focus on current therapeutic agents developed to counteract their aberrant functions, accompanied with discussions of two major challenges to the RTKs-targeted therapy in cancer - resistance and toxicity.

Relevance of Detection of Mechanisms of Resistance to ALK Inhibitors in ALK-Rearranged NSCLC in Routine Practice

BACKGROUND

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) have shown efficacy in the treatment of ALK-rearranged non-small-cell lung cancer (NSCLC), but the disease eventually progresses in all patients. In many cases, resistance to ALK TKIs arises through ALK mutations. Although clinical and biological data suggest variations in TKI efficacy according to the mechanism of resistance, ALK mutations are still rarely investigated in routine practice.

MATERIALS AND METHODS

We performed a retrospective multicentric study with an aim to determine the frequency and clinical relevance of ALK alterations detected using targeted next-generation sequencing in patients with advanced ALK-rearranged NSCLC after progression during an ALK TKI treatment. Data on clinical, pathological, and molecular characteristics and patient outcomes were collected.

RESULTS

We identified 23 patients with advanced ALK-rearranged NSCLC who, between January 2012 and May 2017, had undergone at least 1 repeat biopsy at progression during an ALK TKI treatment. A resistance mechanism was identified in 9 of the 23 patients (39%). The anomalies involved included 9 ALK mutations in 8 patients and one ALK amplification. The ALK mutation rate was 15% after failure of a first ALK TKI and 33% after failure of 2 ALK TKI treatments. Five of 7 patients who received a different ALK TKI after detection of an ALK mutation achieved an objective response. All of the patients who received a TKI presumed to act on the detected ALK mutant achieved disease control.

CONCLUSION

Targeted next-generation sequencing is suitable for detecting ALK resistance mutations in ALK-rearranged NSCLC patients in routine practice. It might help select the best treatment at the time of disease progression during treatment with an ALK TKI.

miR-100-5p confers resistance to ALK tyrosine kinase inhibitors Crizotinib and Lorlatinib in EML4-ALK positive NSCLC

Lung cancer causes the highest number of cancer-related deaths worldwide. Resistance to therapy is a major clinical issue contributing to the poor prognosis of lung cancer. In recent years, targeted therapy has become a concept where subgroups of non-small cell lung cancer (NSCLC) with genetically altered receptor tyrosine kinases are targeted by tyrosine kinase inhibitors (TKIs). One such subgroup harbors a gene fusion of echinoderm microtubule-associated protein-like 4 (EML4) with anaplastic lymphoma kinase (ALK). Although most NSCLC patients with EML4-ALK fusions initially respond to ALK TKI-therapy they eventually develop resistance. While ALK kinase domain mutations contribute to ALK TKI-refractoriness, they are only present in a fraction of all ALK TKI-resistant tumors. In this study we sought to explore a possible involvement of microRNAs (miRNAs) in conferring resistance to ALK TKIs in ALK TKI-refractory NSCLC cell lines. We subjected our ALK TKI-refractory cancer cells along with parental cancer cells to systematic miRNA expression arrays. Furthermore, ALK TKI-refractory cancer cells were exposed to a synthetic miRNA inhibitory Locked Nucleic Acid (LNA)-library in the presence of ALK TKIs Crizotinib or Lorlatinib. The outcome of the combined approaches uncovered miR-100-5p to confer resistance to Crizotinib and Lorlatinib in EML4-ALK NSCLC cells and to be a potential therapeutic target in drug resistance.

Discovery of fluorescent 3-heteroarylcoumarin derivatives as novel inhibitors of anaplastic lymphoma kinase

Coumarin-based ALK inhibitors were identified as a new template for the development of novel fluorescent ALK inhibitors, which can be tracked using microscopy techniques.

Advanced Non-Small Cell Lung Cancer: Sequencing Agents in the EGFR-Mutated/ALK-Rearranged Populations

Personalized therapy based on actionable molecular markers has completely transformed the therapeutic landscape in advanced non-small cell lung cancer (NSCLC). In less than 15 years, multiple molecular targets, led by EGFR and anaplastic lymphoma kinase (ALK), have been identified, and myriad oral tyrosine kinase inhibitors (TKIs) are now available to target these oncogenic drivers, with the expectation that the majority of patients will respond to treatment and that progression-free survival (PFS) will exceed 10 to 30 months, far better than we observed historically with chemotherapy alone. As a result, prognosis has improved dramatically in this subset of patients. Osimertinib has largely displaced first- and second-generation EGFR TKIs, including gefitinib, erlotinib, and afatinib, in the management of EGFR-mutated NSCLC. PFS now exceeds 18 months, and central nervous system penetrance is enhanced. Dacomitinib has the distinction of being the first EGFR TKI to demonstrate a survival advantage compared with older TKIs. Recent data suggest therapeutic additivity, if not synergy, for the concurrent use of chemotherapy, as well as monoclonal antibodies targeting angiogenesis, with EGFR TKIs. Alectinib and brigatinib, very specific ALK inhibitors, have proven superior to the erstwhile standard crizotinib in treatment-naive ALK+ NSCLC; PFS now routinely exceeds 2 to 3 years. In addition, these newer agents have far superior central nervous system penetration. As a result, many patients with ALK+ advanced NSCLC with brain metastases, even some who are symptomatic, can defer or indefinitely avoid brain irradiation. Mechanisms of resistance in ALK are complicated, with multiple new agents being developed in this arena. Although many patients with molecular targets can reasonably expect to live 5 years or more, the emergence of molecular resistance is virtually inevitable. In this regard, systemic platinum-based chemotherapy is the final common therapeutic pathway for virtually all patients with oncogenic drivers. Standard regimens include pemetrexed and carboplatin, as well as the E4599 regimen, combination solvent-based paclitaxel, carboplatin, and bevacizumab. Checkpoint inhibitors, as single agents, have not yielded much benefit, even in those with high levels of PD-L1 expression. However, in a subanalysis of patients with ALK and EGFR mutations enrolled in IMpower150, the addition of atezolizumab to the E4599 regimen led to a major overall survival benefit (hazard ratio < 0.40). In the absence of systemic chemotherapy, combining checkpoint inhibitors with TKIs in this setting remains investigational; several studies have demonstrated untoward pulmonary and hepatic toxicity.

Targeted therapies for advanced non-small cell lung cancer

Lung cancer is a serious health problem and the leading cause of cancer death worldwide, due to its high incidence and mortality. 85% of lung cancers are represented by the non-small cell lung cancer (NSCLC). Traditional chemotherapy has been the main treatment option in NSCLC. However, it is often associated with limited efficacy and overall poor patient survival. In recent years, molecular targeting has achieved great progress in therapeutic treatment of cancer and plays a crucial role in the current clinical treatment of NSCLC, due to enhanced efficacy on cancer tissues and reduced toxicity for normal tissues. In this review, we summarize the current targeting treatment of NSCLC, including inhibition of the epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3Ks), mechanistic target of rapamycin (mTOR), epidermal growth factor receptor 2 (ErbB2), vascular epidermal growth factor receptor (VEGFR), kirsten human rat sarcoma protein (KRAS), mesenchymal-epithelial transition factor or hepatocyte growth factor receptor (c-MET), anaplastic lymphoma kinase (ALK), v-Raf murine sarcoma viral oncogene homolog B (BRAF). This article may serve as a guide to clinicians and researchers alike by assisting in making therapeutic decisions. Challenges of acquired drug resistance targeted therapy and imminent newer treatment modalities against NSCLC are also discussed.

Amplification of Wild-type KRAS Imparts Resistance to Crizotinib in MET Exon 14 Mutant Non-Small Cell Lung Cancer

PURPOSE

MET inhibitors can be effective therapies in patients with MET exon 14 (METex14) mutant non-small cell lung cancer (NSCLC). However, long-term efficacy is limited by the development of drug resistance. In this study, we characterize acquired amplification of wild-type (WT) KRAS as a molecular mechanism behind crizotinib resistance in three cases of METex14-mutant NSCLC and propose a combination therapy to target it.

EXPERIMENTAL DESIGN

The patient-derived cell line and xenograft (PDX) DFCI358 were established from a crizotinib-resistant METex14-mutant patient tumor with massive focal amplification of WT KRAS. To characterize the mechanism of KRAS-mediated resistance, molecular signaling was analyzed in the parental cell line and its KRAS siRNA-transfected derivative. Sensitivity of the cell line to ligand stimulation was assessed and KRAS-dependent expression of EGFR ligands was quantified. Drug combinations were screened for efficacy in vivo and in vitro using viability and apoptotic assays.

RESULTS

KRAS amplification is a recurrent genetic event in crizotinib-resistant METex14-mutant NSCLC. The key characteristics of this genetic signature include uncoupling MET from downstream effectors, relative insensitivity to dual MET/MEK inhibition due to compensatory induction of PI3K signaling, KRAS-induced expression of EGFR ligands and hypersensitivity to ligand-dependent and independent activation, and reliance on PI3K signaling upon MET inhibition.

CONCLUSIONS

Using patient-derived cell line and xenografts, we characterize the mechanism of crizotinib resistance mediated by KRAS amplification in METex14-mutant NSCLC and demonstrate the superior efficacy of the dual MET/PI3K inhibition as a therapeutic strategy addressing this resistance mechanism.

CT-707 Overcomes Resistance of Crizotinib through Activating PDPK1- AKT1 Pathway by Targeting FAK

BACKGROUND

Crizotinib established the position of anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKI) in the treatment of non-small cell lung cancer (NSCLC) while the therapy- resistance hindered those patients from benefitting continuously from the treatment. CT-707 is an inhibitor of ALK/focal adhesion kinase (FAK) and IGFR-1. H2228CR (crizotinib resistance, CR) and H3122CR NSCLC cell lines were generated from the parental cell line H2228 (EML4-ALK, E6a/b:A20, variant 3) and H3122(EML4-ALK, E13:A20, variant 1), respectively.

METHODS

We investigated the antitumor effects CT-707 exerted against H3122CR in vitro /vivo.

RESULTS

Importantly, our study provided evidence that CT-707 overcomes resistance to crizotinib through activating PDPK1-AKT1 pathway by targeting FAK. Meanwhile, by using an in-vivo H3122CR xenograft model, we found CT-707 inhibited tumor growth significantly without obvious side effects.

CONCLUSION

These findings indicate that CT-707 may be a promising therapeutic agent against crizotinib- resistance in NSCLC.

[Advances in Double Mutations of EGFR and ALK Gene in Non-small Cell Lung Cancer]

Molecular target therapy is one of the most popular field of non-small cell lung cancer (NSCLC) treatmnet. Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearragement are the most important two oncogenic drivers in NSCLC, early studies suggested that EGFR mutations and ALK rearrangements are mutually exclusive, but isolated cases or small sample research with concomitant EGFR and ALK alterations have been constantly reported. The co-occurrence of EGFR mutations and anaplastic lymphoma kinase (ALK) rearrangements constitutes a rare molecular, the frequency of EGFR/ALK co-alterations was about 1%, however, little has been known about clinicopathologic feature and treatment. This review summarized published case report, EGFR and ALK alterations are common in female, Asian origin, never smoker, IV stage, and denocarcinomas. First-line treatment can choose EGFR or ALK tyrosine kinase inhibitors (TKIs). However, studies about the origin and resistance mechanism in EGFR/ALK co-alterations are little, require more experimental and clinical research.
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Acquired resistance in oncogene-addicted non-small-cell lung cancer

The advance of tyrosine kinase inhibitors has profoundly changed the therapeutic algorithm of non-small-cell lung cancer in molecularly selected patients. However, benefit from these agents is often transient and usually most patients progress within 12 months from treatment. Novel and more potent and selective tyrosine kinase inhibitors have been developed to overcome acquired resistance; however, these agents are once again associated with only temporary benefit and patients frequently develop secondary resistance, a heterogeneous phenomenon that involves different molecular mechanisms simultaneously. The aim of our paper is to provide a comprehensive overview of the mechanisms of acquired resistance in oncogene-addicted non-small-cell lung cancer, focusing on the two most studied target, EGFR mutations and ALK translocation, and reviewing the main challenges in clinical practice.

Pulmonary Adenocarcinoma, Harboring Both an EGFR Mutation and ALK Rearrangement, Presenting a Stable Disease to Erlotinib and a Partial Response to Alectinib

A 63-year-old woman with pulmonary adenocarcinoma (stage IIIB) that was positive for an epidermal growth factor receptor (EGFR) mutation and an anaplastic lymphoma kinase (ALK) rearrangement was treated with erlotinib as the first-line treatment, resulting in a stable disease. Due to skin rashes, fatigue and anorexia, erlotinib was suspended on erlotinib day 44. Alectinib was administered as the second-line treatment, exhibiting a partial response. On alectinib day 56, drug-induced lung injury forced suspension of alectinib, which was cured with corticosteroid therapy. ALK-tyrosine kinase inhibitors may be more effective for patients positive for both EGFR mutation and ALK rearrangement than other agents.

Emerging findings into molecular mechanism of brain metastasis

Brain metastasis is an important cause of morbidity and mortality in cancer patients. Hence, the need to develop improved therapies to prevent and treat metastasis to the brain is becoming urgent. Recent studies in this area are bringing about some advanced progress on brain metastasis. It was concluded that the occurrence and poor prognosis of brain metastasis have been mostly attributed to the exclusion of anticancer drugs from the brain by the blood-brain barrier. And several highly potent new generation targeted drugs with enhanced CNS distribution have been developed constantly. However, the noted "seed and soil" hypothesis also suggests that the outcome of metastasis depends on the relationship between unique tumor cells and the specific organ microenvironment. Moreover, increasing studies in multiple tumor types demonstrated that brain metastasis has great molecular differences between primary tumors and extracranial metastasis to a large extent. Here, the authors summarized the most common malignancies that could lead to brain metastasis-lung cancer, breast cancer and melanoma and their related mutated factors. Only by comprehending a deeper understanding of the molecular mechanisms, more effective brain-specific therapies will be developed for brain metastasis.

The brigatinib experience: a new generation of therapy for ALK-positive non-small-cell lung cancer

Lung cancer remains the leading cause of cancer deaths in the world with 1.69 million deaths in 2015. A total of 85% of lung cancer cases are non-small-cell lung cancers (NSCLCs). Driver mutations associated with anaplastic lymphoma kinase (ALK) have been identified in a variety of malignancies, including NSCLC. An ALK inhibitor (crizotinib, ceritinib and alectinib) is the preferred therapeutic approach to those advanced ALK fusion variant-positive NSCLC patients. Brigatinib, a next-generation ALK inhibitor, shows promising activity in ALK-rearranged NSCLC that have previously received crizotinib with response rates in ALTA ranging from 42–50%, intracranial response 42–67% and median progression-free survival 9.2–12.9 months. Randomized Phase III trial, ALTA-1 L is investigating brigatinib in ALK inhibitor-naive patients.

Serum ProGRP and NSE levels predicting small cell lung cancer transformation in a patient with ALK rearrangement-positive non-small cell lung cancer: A case report

The resistance mechanisms to anaplastic lymphoma kinase (ALK) inhibitors comprise ALK gene variations, such as ALK point mutations and copy-number gains, the activation of bypass signaling through the activation of other oncogenes and small cell lung cancer (SCLC) transformation. To date, few studies have investigated whether tumor markers for SCLC correlate with the SCLC transformation in EGFR-mutant NSCLC and ALK-positive non-SCLC (NSCLC). The present case study reported a patient with SCLC transformation after alectinib treatment. The patient exhibited elevation of pro-gastrin-releasing peptide precursor and neuron-specific enolase levels, which may be predictive of SCLC transformation during the resistance to ALK-tyrosine kinase inhibitors.

Structure and energy based quantitative missense variant effect analysis provides insights into drug resistance mechanisms of anaplastic lymphoma kinase mutations

Anaplastic lymphoma kinase (ALK) is considered as a validated molecular target in multiple malignancies, such as non-small cell lung cancer (NSCLC). However, the effectiveness of molecularly targeted therapies using ALK inhibitors is almost universally limited by drug resistance. Drug resistance to molecularly targeted therapies has now become a major obstacle to effective cancer treatment and personalized medicine. It is of particular importance to provide an improved understanding on the mechanisms of resistance of ALK inhibitors, thus rational new therapeutic strategies can be developed to combat resistance. We used state-of-the-art computational approaches to systematically explore the mutational effects of ALK mutations on drug resistance properties. We found the activation of ALK was increased by substitution with destabilizing mutations, creating the capacity to confer drug resistance to inhibitors. In addition, results implied that evolutionary constraints might affect the drug resistance properties. Moreover, an extensive profile of drugs against ALK mutations was constructed to give better understanding of the mechanism of drug resistance based on structural transitions and energetic variation. Our work hopes to provide an up-to-date mechanistic framework for understanding the mechanisms of drug resistance induced by ALK mutations, thus tailor treatment decisions after the emergence of resistance in ALK-dependent diseases.

Targeting CCR2 with its antagonist suppresses viability, motility and invasion by downregulating MMP-9 expression in non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, which is the leading cancer killer in the world. Despite the recent advances in its diagnosis and therapy, the prognosis of NSCLC patients remains very poor, mainly due to the development of drug resistance and metastasis. Both the chemokine network and the matrix metalloproteinase (MMP) system play important roles in cancer cell metastasis. The disruption of CCL2/CCR2 chemokine signaling has been shown to suppress cancer cellviability and metastasis. CCL2-neutralizing antibodies, which have shown promising therapeutic efficacy in several cancer models, are not widely used due to technical issues. CCR2 antagonism has thus become an alternative method for cancer treatment. However, the effect of CCR2 antagonists on NSCLC progression remains poorly understood. Here, we investigated the effect of CCR2 antagonist (CAS445479-97-0) on the proliferation, migration and invasion of human lung adenocarcinoma A549 cells by using WST-1 cell viability assay, transwell migration assay, wound healing scratch assay and Matrigel invasion assay. We demonstrated that CCL2 treatment promoted A549 cell viability, motility and invasion by upregulating MMP-9 expression and that this induction was significantly suppressed by CAS 445479-97-0. Taken together, our data suggested that the CCR2 antagonist would be a potential drug for treating CCR2-positive NSCLC patients.

Overcoming drug-tolerant cancer cell subpopulations showing AXL activation and epithelial-mesenchymal transition is critical in conquering ALK-positive lung cancer

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) induce a dramatic response in non-small cell lung cancer (NSCLC) patients with the ALK fusion gene. However, acquired resistance to ALK-TKIs remains an inevitable problem. In this study, we aimed to discover novel therapeutic targets to conquer ALK-positive lung cancer. We established three types of ALK-TKI (crizotinib, alectinib and ceritinib)-resistant H2228 NSCLC cell lines by high exposure and stepwise methods. We found these cells showed a loss of ALK signaling, overexpressed AXL with epithelial-mesenchymal transition (EMT), and had cancer stem cell-like (CSC) properties, suggesting drug-tolerant cancer cell subpopulations. Similarly, we demonstrated that TGF-β1 treated H2228 cells also showed AXL overexpression with EMT features and ALK-TKI resistance. The AXL inhibitor, R428, or HSP90 inhibitor, ganetespib, were effective in reversing ALK-TKI resistance and EMT changes in both ALK-TKI-resistant and TGF-β1-exposed H2228 cells. Tumor volumes of xenograft mice implanted with established H2228-ceritinib-resistant (H2228-CER) cells were significantly reduced after treatment with ganetespib, or ganetespib in combination with ceritinib. Some ALK-positive NSCLC patients with AXL overexpression showed a poorer response to crizotinib therapy than patients with a low expression of AXL. ALK signaling-independent AXL overexpressed in drug-tolerant cancer cell subpopulations with EMT and CSC features may be commonly involved commonly involved in intrinsic and acquired resistance to ALK-TKIs. This suggests AXL and HSP90 inhibitors may be promising therapeutic drugs to overcome drug-tolerant cancer cell subpopulations in ALK-positive NSCLC patients for the reason that ALK-positive NSCLC cells do not live through ALK-TKI therapy.

Neutral Theory and the Somatic Evolution of Cancer

Kimura's neutral theory argued that positive selection was not responsible for an appreciable fraction of molecular substitutions. Correspondingly, quantitative analysis reveals that the vast majority of substitutions in cancer genomes are not detectably under selection. Insights from the somatic evolution of cancer reveal that beneficial substitutions in cancer constitute a small but important fraction of the molecular variants. The molecular evolution of cancer community will benefit by incorporating the neutral theory of molecular evolution into their understanding and analysis of cancer evolution-and accepting the use of tractable, predictive models, even when there is some evidence that they are not perfect.

Cost-effectiveness of ceritinib in previously untreated anaplastic lymphoma kinase-positive metastatic non-small cell lung cancer in the United States

AIMS

To assess the cost-effectiveness of first-line ceritinib vs crizotinib and platinum doublet chemotherapy for anaplastic lymphoma kinase (ALK)-positive metastatic non-small cell lung cancer (NSCLC) from a US third-party payer's perspective.

MATERIALS AND METHODS

A partitioned survival model with three health states (stable disease, progressive disease, death) was developed over a 20-year time horizon. Ceritinib's efficacy inputs (progression-free and overall survival) were estimated from ASCEND-4; parametric survival models extrapolated data beyond the trial period. The relative efficacy of ceritinib vs chemotherapy was obtained from ASCEND-4, the relative efficacy of ceritinib vs crizotinib was estimated using a matching-adjusted indirect comparison based on ASCEND-4 and PROFILE 1014. Drug acquisition, treatment administration, adverse event management, and medical costs were obtained from publicly available databases and the literature, and inflated to 2016 US dollars. Treatment-specific stable-state utilities were derived from trials and progressive-state utility from the literature. Incremental costs per quality-adjusted life year (QALY) were estimated for ceritinib vs each comparator. Cost-effectiveness was assessed based on US willingness-to-pay thresholds. Deterministic and probabilistic sensitivity analyses were performed to test model robustness.

RESULTS

In the base case, first-line ceritinib was associated with total direct costs of $299,777 and 3.28 QALYs (from 4.61 life years gained [LYG]) over 20 years. First-line crizotinib and chemotherapy were associated with 2.73 and 2.41 QALYs, 3.92 and 3.53 LYG, and $263,172 and $228,184 total direct costs, respectively. The incremental cost per QALY gained was $66,064 for ceritinib vs crizotinib and $81,645 for ceritinib vs chemotherapy. In the first 2 years following treatment initiation, ceritinib dominated crizotinib by conferring greater health benefits at reduced total costs. Results were robust to deterministic and probabilistic sensitivity analyses.

LIMITATIONS

In the absence of head-to-head trials, an indirect comparison method was used.

CONCLUSIONS

Ceritinib is cost-effective compared to crizotinib and chemotherapy in the treatment of previously untreated ALK-positive metastatic NCSLC in the US.

A Convergence-Based Framework for Cancer Drug Resistance

Despite advances in cancer biology and therapeutics, drug resistance remains problematic. Resistance is often multifactorial, heterogeneous, and prone to undersampling. Nonetheless, many individual mechanisms of targeted therapy resistance may coalesce into a smaller number of convergences, including pathway reactivation (downstream re-engagement of original effectors), pathway bypass (recruitment of a parallel pathway converging on the same downstream output), and pathway indifference (development of a cellular state independent of the initial therapeutic target). Similar convergences may also underpin immunotherapy resistance. Such parsimonious, convergence-based frameworks may help explain resistance across tumor types and therapeutic categories and may also suggest strategies to overcome it.

Latest perspectives of orally bioavailable 2,4-diarylaminopyrimidine analogues (DAAPalogues) as anaplastic lymphoma kinase inhibitors: discovery and clinical developments

The course of anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung cancer (NSCLC) therapy has improved impressively. The Food and Drug Administration (FDA) has approved crizotinib (Xalkori, Pfizer) as a first-in-class tyrosine kinase inhibitor (TKI) that demonstrated a substantial objective response rate (ORR) and remarkable progression-free survival (PFS). However, acquired resistance to crizotinib is still a major concern especially as the central nervous system (CNS) remains the most common sites of relapse. To combat disease resistance, limited PFS and poor CNS exposure exhibited by crizotinib (Xalkori, Pfizer) led to the discovery of numerous next generation ALK-TKIs and surprisingly most of them are 2,4-Diarylaminopyrimidine Analogues (DAAPalogues). To date, DAAPalogues have been investigated extensively to display their superior potency against numerous kinase targets especially ALK/ROS1. This review describes hit-to-drug evolution strategies, activity spectra, milestones related to medicinal chemistry discovery efforts and scalable synthetic pathways of clinically emerging DAAPalouges which are either progressing as investigational or preclinical candidates. In addition, the significance of DAAPalogues to treat the patients with ALK+-NSCLC in clinical settings has been detailed. This review is beneficial for medicinal chemists and researchers contributing to discovering ALK-TKIs to overcome existing issues related to DAAPalouges in the drug discovery process.

Synchronous Presence of EGFR, ALK Driver Mutations Along With PD L1 Overexpression in a Resected Early Stage Non-Small Cell Lung Cancer: A Case Report and Review of Literature

Treatment of lung cancer has been revolutionized with development of drugs that target key driver mutations and immune checkpoints. Until recently, it was believed that these driver mutations are mutually exclusive. However, few reports have emerged citing the presence of both mutations either synchronously or metachronously. We describe a case report of lung adenocarcinoma harboring two driver mutations in the same tumor cells as well as exhibiting high PDL1 expression. We further discuss the possible association of these driver mutations with PDL1 expression.

Genomic heterogeneity of ALK fusion breakpoints in non-small-cell lung cancer

In lung adenocarcinoma, canonical EML4-ALK inversion results in a fusion protein with a constitutively active ALK kinase domain. Evidence of ALK rearrangement occurs in a minority (2-7%) of lung adenocarcinoma, and only ~60% of these patients will respond to targeted ALK inhibition by drugs such as crizotinib and ceritinib. Clinically, targeted anti-ALK therapy is often initiated based on evidence of an ALK genomic rearrangement detected by fluorescence in situ hybridization (FISH) of interphase cells in formalin-fixed, paraffin-embedded tissue sections. At the genomic level, however, ALK rearrangements are heterogeneous, with multiple potential breakpoints in EML4, and alternate fusion partners. Using next-generation sequencing of DNA and RNA together with ALK immunohistochemistry, we comprehensively characterized genomic breakpoints in 33 FISH-positive lung adenocarcinomas. Of these 33 cases, 29 (88%) had detectable DNA level ALK rearrangements involving EML4, KIF5B, or non-canonical partners including ASXL2, ATP6V1B1, PRKAR1A, and SPDYA. A subset of 12 cases had material available for RNA-Seq. Of these, eight of eight (100%) cases with DNA rearrangements showed ALK fusion transcripts from RNA-Seq; three of four cases (75%) without detectable DNA rearrangements were similarly negative by RNA-Seq, and one case was positive by RNA-Seq but negative by DNA next-generation sequencing. By immunohistochemistry, 17 of 19 (89%) tested cases were clearly positive for ALK protein expression; the remaining cases had no detectable DNA level rearrangement or had a non-canonical rearrangement not predicted to form a fusion protein. Survival analysis of patients treated with targeted ALK inhibitors demonstrates a significant difference in mean survival between patients with next-generation sequencing confirmed EML4-ALK rearrangements, and those without (20.6 months vs 5.4 months, P<0.01). Together, these data demonstrate abundant genomic heterogeneity among ALK-rearranged lung adenocarcinoma, which may account for differences in treatment response with targeted ALK inhibitors.

Clinical benefit of continuing crizotinib therapy after initial disease progression in Chinese patients with advanced ALK-rearranged non-small-cell lung cancer

Purpose

Although most patients with ALK-positive non?small-cell lung cancer (NSCLC) who benefit from treatment with crizotinib ultimately develop progressive disease (PD), continuing crizotinb beyond the initial PD (CBPD) in these patients may be beneficial. In this study, we investigated whether Chinese patients with advanced ALK-positive NSCLC benefit from CBPD, and whether any factors are predictive of a longer post-initial progression-free survival time (PFS2).

Materials and Methods

Data on 33 patients with ALK-positive NSCLC who achieved disease control with crizotinib were analyzed retrospectively. The impact of continued crizotinib therapy on the patients’ PFS2 time was assessed after adjusting for potential confounding factors.

Results

With initial crizotinib therapy, the objective response rate (ORR) and median PFS time (PFS1) in the 33 patients were 63.6% and 8.6 months, respectively. With continued crizotinib therapy after documentation of PD, the median PFS2 for all 33 patients was 16 weeks, and in those with CNS progression but systemic disease control it was 30 weeks. Patients who received local therapy after disease progression had a significantly longer PFS2 compared with those who did not (P = 0.039). Multivariable Cox regression analysis showed that the PFS1 with initial crizotinib treatment and local therapy were independent predictors of PFS2.

Discussion

This study provides further evidence of the benefit of continuing crizotinib therapy in Chinese patients with progressive ALK-positive NSCLC. Patients with a longer PFS1 and those who received local brain therapy would have a longer period of continuing crizotinib.

Enhancer Remodeling and MicroRNA Alterations Are Associated with Acquired Resistance to ALK Inhibitors

Anaplastic lymphoma kinase (ALK) inhibitors are highly effective in patients with ALK fusion-positive lung cancer, but acquired resistance invariably emerges. Identification of secondary mutations has received considerable attention, but most cases cannot be explained by genetic causes alone, raising the possibility of epigenetic mechanisms in acquired drug resistance. Here, we investigated the dynamic changes in the transcriptome and enhancer landscape during development of acquired resistance to ALK inhibitors. Histone H3 lysine 27 acetylation (H3K27ac) was profoundly altered during acquisition of resistance, and enhancer remodeling induced expression changes in both miRNAs and mRNAs. Decreased H3K27ac levels and reduced miR-34a expression associated with the activation of target genes such as AXL. Panobinostat, a pan-histone deacetylase inhibitor, altered the H3K27ac profile and activated tumor-suppressor miRNAs such as miR-449, another member of the miR-34 family, and synergistically induced antiproliferative effects with ALK inhibitors on resistant cells, xenografts, and EML4-ALK transgenic mice. Paired analysis of patient samples before and after treatment with ALK inhibitors revealed that repression of miR-34a or miR-449a and activation of AXL were mutually exclusive of secondary mutations in ALK. Our findings indicate that enhancer remodeling and altered expression of miRNAs play key roles in cancer drug resistance and suggest that strategies targeting epigenetic pathways represent a potentially effective method for overcoming acquired resistance to cancer therapy.Significance: Epigenetic deregulation drives acquired resistance to ALK inhibitors in ALK-positive lung cancer. Cancer Res; 78(12); 3350-62. ©2018 AACR.

Precision medicine against ALK-positive non-small cell lung cancer: beyond crizotinib

Anaplastic lymphoma kinase (ALK) rearrangements represent the molecular driver of a subset of non-small cell lung cancers (NSCLCs). Despite the initial response, virtually all ALK-positive patients develop an acquired resistance to the ALK inhibitor crizotinib, usually within 12 months. Several next-generation ALK inhibitors have been developed in order to overcome crizotinib limitation, providing an unprecedented survival for this subset of patients. The aim of this review to summarize the current knowledge on ALK tyrosine kinase inhibitors (TKIs) in the treatment of advanced ALK-positive NSCLC, focusing on the role of novel ALK inhibitors in this setting. In addition, we will discuss their role in the pharmacological management of ALK-positive brain metastasis. Next-generation ALK inhibitors showed an impressive clinical activity in ALK-positive NSCLC, also against the sanctuary site of CNS. Sequential therapy with ALK TKIs appears to be effective in patients who fail a first ALK TKI and translates in clinically meaningful benefit. However, these agents display different activity profiles against crizotinib resistance mutation; therefore re-genotyping the disease at progression in order to administer the right TKI to the right patient is going to be necessary to correctly tailor the treatment. To avoid repeated invasive procedure, noninvasive methods to detect and monitor ALK rearrangement are under clinical investigation.

Resistance Mechanisms to Targeted Therapies in ROS1+ and ALK+ Non-small Cell Lung Cancer

Purpose: Despite initial benefit from tyrosine kinase inhibitors (TKIs), patients with advanced non-small cell lung cancer (NSCLC) harboring ALK (ALK⁺) and ROS1 (ROS1⁺) gene fusions ultimately progress. Here, we report on the potential resistance mechanisms in a series of patients with ALK⁺ and ROS1⁺ NSCLC progressing on different types and/or lines of ROS1/ALK-targeted therapy.Experimental Design: We used a combination of next-generation sequencing (NGS), multiplex mutation assay, direct DNA sequencing, RT-PCR, and FISH to identify fusion variants/partners and copy-number gain (CNG), kinase domain mutations (KDM), and copy-number variations (CNVs) in other cancer-related genes. We performed testing on 12 ROS1⁺ and 43 ALK⁺ patients.Results: One of 12 ROS1⁺ (8%) and 15 of 43 (35%) ALK ⁺ patients harbored KDM. In the ROS1⁺ cohort, we identified KIT and β-catenin mutations and HER2-mediated bypass signaling as non-ROS1-dominant resistance mechanisms. In the ALK⁺ cohort, we identified a novel NRG1 gene fusion, a RET fusion, 2 EGFR, and 3 KRAS mutations, as well as mutations in IDH1, RIT1, NOTCH, and NF1 In addition, we identified CNV in multiple proto-oncogenes genes including PDGFRA, KIT, KDR, GNAS, K/HRAS, RET, NTRK1, MAP2K1, and others.Conclusions: We identified a putative TKI resistance mechanism in six of 12 (50%) ROS1 ⁺ patients and 37 of 43 (86%) ALK⁺ patients. Our data suggest that a focus on KDMs will miss most resistance mechanisms; broader gene testing strategies and functional validation is warranted to devise new therapeutic strategies for drug resistance. Clin Cancer Res; 24(14); 3334-47. ©2018 AACR.

Gene status and clinicopathologic characteristics of lung adenocarcinomas with mediastinal lymph node metastasis

Lung cancer with mediastinal lymph node metastasis is more likely to develop recurrence and metastasis after complete resection and targeted therapy is a promising treatment strategy. We performed amplification refractory mutation system (ARMS) fluorescence quantitative PCR to detect the gene status of EGFR, ALK, ROS1 and RET in resected samples from 280 patients who were confirmed to have primary lung adenocarcinomas with N1-N2 lymph node metastasis. Of the 280 patients enrolled, the frequency of EGFR mutations, ALK fusions, ROS1 fusions, RET fusions and no mutations was 42.9%, 10.7%, 1.8%, 3.6% and 42.9%, respectively. Five patients exhibited the coexistence of the EGFR and ALK alterations. ALK, ROS1 and RET fusions were mutually exclusive. The frequency of EGFR mutation was significantly lower among patients with poor differentiation, while the rates of ALK and ROS1 fusions were the opposite. RET fusions also tended to be more prevalent in poorly differentiated patients. EGFR and ALK double positive tumors were characterized by significantly smaller size compared with those had single gene alteration. Our study comprehensively analyzed the distinct and common clinicopathologic characteristics according to genotypes of the cohort, which should help in categorizing patients for efficient screening.

The Pathological Spectrum of Systemic Anaplastic Large Cell Lymphoma (ALCL)

Anaplastic large cell lymphoma (ALCL) represents a group of malignant T-cell lymphoproliferations that share morphological and immunophenotypical features, namely strong CD30 expression and variable loss of T-cell markers, but differ in clinical presentation and prognosis. The recognition of anaplastic lymphoma kinase (ALK) fusion proteins as a result of chromosomal translocations or inversions was the starting point for the distinction of different subgroups of ALCL. According to their distinct clinical settings and molecular findings, the 2016 revised World Health Organization (WHO) classification recognizes four different entities: systemic ALK-positive ALCL (ALK+ ALCL), systemic ALK-negative ALCL (ALK− ALCL), primary cutaneous ALCL (pC-ALCL), and breast implant-associated ALCL (BI-ALCL), the latter included as a provisional entity. ALK is rearranged in approximately 80% of systemic ALCL cases with one of its partner genes, most commonly NPM1, and is associated with favorable prognosis, whereas systemic ALK− ALCL shows heterogeneous clinical, phenotypical, and genetic features, underlining the different oncogenesis between these two entities. Recognition of the pathological spectrum of ALCL is crucial to understand its pathogenesis and its boundaries with other entities. In this review, we will focus on the morphological, immunophenotypical, and molecular features of systemic ALK+ and ALK− ALCL. In addition, BI-ALCL will be discussed.

Treating ALK-positive non-small cell lung cancer

Targeting genomic alterations, such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) gene rearrangements, have radically changed the treatment of patients with non-small cell lung cancer (NSCLC). In the case of ALK-rearranged gene, subsequent rapid development of effective genotype-directed therapies with ALK tyrosine kinase inhibitors (TKIs) triggered major advances in the personalized molecularly based approach of NSCLC. Crizotinib was the first-in-class ALK TKI with proven superiority over standard platinum-based chemotherapy for the 1st-line therapy of ALK-rearranged NSCLC patients. However, the acquired resistance to crizotinib and its diminished efficacy to the central nervous system (CNS) relapse led to the development of several novel ALK inhibitors, more potent and with different selectivity compared to crizotinib. To date, four ALK TKIs, crizotinib, ceritinib, alectinib and brigatinib have received approval from the Food and Drug Administration (FDA) and/or the European Medicines Agency (EMA) and even more agents are currently under investigation for the treatment of ALK-rearranged NSCLC. However, the optimal frontline approach and the exact sequence of ALK inhibitors are still under consideration. Recently announced results of phase III trials recognized higher efficacy of alectinib compared to crizotinib in first-line setting, even in patients with CNS involvement. In this review, we will discuss the current knowledge regarding the biology of the ALK-positive NSCLC, the available therapeutic inhibitors and we will focus on the raised issues from their use in clinical practise.

Treatment patterns, clinical and economic outcomes of patients with anaplastic lymphoma kinase-positive non-small cell lung cancer receiving ceritinib: a retrospective observational claims analysis

Objective: To describe patient characteristics, treatment patterns, healthcare resource utilization (HRU), and costs among patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) receiving ceritinib in second or later line of therapy.

Methods: Adult patients with NSCLC receiving ceritinib were identified from two large US claims databases (2006–2015). Patient characteristics, comorbidity profile, treatment patterns prior to ceritinib, and ceritinib dosing patterns were described. All-cause, HRU, and costs incurred during the observation period after ceritinib initiation were reported per patient per six months.

Results: One hundred sixty-four patients were included (mean age 54.2 years, 57.3% female); the majority had metastatic disease (94.5%) and the average Charlson Comorbidity Index was 7.6. 150 (91.5%) patients received crizotinib prior to ceritinib – average crizotinib duration was 10.2 months and time between crizotinib discontinuation and ceritinib initiation was 2.1 months (median= 0; 25th–75th percentile= 0–0.8). Most patients (73.8%) initiated ceritinib on the recommended dose (750 mg) and maintained the dose until the end of the observation period (mean of 7.4 months) or ceritinib discontinuation; 61 (37.2%) patients discontinued ceritinib during the observation period. A total of 76 (46.3%) patients had at least one inpatient admission during the observation period after ceritinib initiation. Mean total healthcare cost per patient per six months was $111,468.

Conclusions: Patients with ALK-positive NSCLC receiving ceritinib had a high comorbidity burden and generally started ceritinib on the recommended dose quickly after crizotinib discontinuation. Medical costs accounted for nearly a half of the total healthcare costs.

Background and rationale of the eXalt3 trial investigating X-396 in the treatment of ALK+ non-small-cell lung cancer

Despite significant advancements in the treatment of anaplastic lymphoma kinase (ALK) positive non-small-cell lung cancer (NSCLC) since the advent of crizotinib, the development of acquired resistance and poor CNS efficacy have necessitated the search for novel and more robust therapies. Ensartinib (X-396) is a novel second-generation ALK-tyrosine kinase inhibitor (TKI) that holds much clinical promise. Preclinical data have demonstrated increased potency of the drug as compared with crizotinib and other second-generation ALK-TKI therapies such as alectinib and ceritinib. This review highlights the first- and second-generation ALK inhibitors approved for the treatment of ALK-positive NSCLC and discusses the clinical trial protocol for the eXalt3 trial (NCT02767804) comparing the efficacy and safety of ensartinib to crizotinib in patients diagnosed with ALK-positive NSCLC who are naive to prior ALK-TKI treatment.

Concurrent gene alterations with EGFR mutation and treatment efficacy of EGFR-TKIs in Chinese patients with non-small cell lung cancer

PURPOSE

We investigated the frequency of concurrent genes in EGFR-mutant non-small cell lung cancer patients and determined its value in predicting the efficacy of EGFR-TKIs treatment.

METHODS

Three hundred and twenty patients, who harbored EGFR activating mutations and received EGFR-TKIs treatment, were examined for another eight genes including KRAS, NRAS, PIK3CA, BRAF, and HER2 mutations and ALK, ROS1, and RET fusion genes based on reverse transcription PCR. Progression-free survival and overall survival with EGFR-TKIs treatment were evaluated using Kaplan-Meier methods and compared between different patients using log-rank tests.

RESULTS

Twenty-one (6.6%) of 320 EGFR mutant samples with additional gene alterations were identified. The most common concurrent gene was PIK3CA mutation (n = 9), followed by EML4-ALK rearrangement (n = 6), HER2 mutation (n = 3), RET rearrangement (n = 1), ROS1 rearrangement (n = 1) and KRAS mutation (n = 1). Patients with single EGFR mutation had a significantly longer progression-free survival than those with concurrent genes (10.9 vs. 6.0 months, P = 0.002). Among the 21 cases, patients with PIK3CA mutation had the longest median progression-free survival (7.6 months), followed by ALK rearrangement (5.0 months) and other gene types (1.2 months). No overall survival difference was found between patients with single EGFR mutation and concurrent gene alterations (21.0 vs.17.6 months, P = 0.17).

CONCLUSION

We demonstrated that concurrent gene alterations occurred in some patients with EGFR mutations. Concurrent gene alterations decreased the efficacy of EGFR-TKIs.

SHP2 inhibition restores sensitivity in ALK-rearranged non-small-cell lung cancer resistant to ALK inhibitors

Most anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung tumors initially respond to small-molecule ALK inhibitors, but drug resistance often develops. Of tumors that develop resistance to highly potent second-generation ALK inhibitors, approximately half harbor resistance mutations in ALK, while the other half have other mechanisms underlying resistance. Members of the latter group often have activation of at least one of several different tyrosine kinases driving resistance. Such tumors are not expected to respond to lorlatinib-a third-generation inhibitor targeting ALK that is able to overcome all clinically identified resistant mutations in ALK-and further therapeutic options are limited. Herein, we deployed a shRNA screen of 1,000 genes in multiple ALK-inhibitor-resistant patient-derived cells (PDCs) to discover those that confer sensitivity to ALK inhibition. This approach identified SHP2, a nonreceptor protein tyrosine phosphatase, as a common targetable resistance node in multiple PDCs. SHP2 provides a parallel survival input downstream of multiple tyrosine kinases that promote resistance to ALK inhibitors. Treatment with SHP099, the recently discovered small-molecule inhibitor of SHP2, in combination with the ALK tyrosine kinase inhibitor (TKI) ceritinib halted the growth of resistant PDCs through preventing compensatory RAS and ERK1 and ERK2 (ERK1/2) reactivation. These findings suggest that combined ALK and SHP2 inhibition may be a promising therapeutic strategy for resistant cancers driven by several different ALK-independent mechanisms underlying resistance.

Tumor Resistance against ALK Targeted Therapy-Where It Comes From and Where It Goes

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, particularly in non-small-cell lung cancer (NSCLC), which has generated considerable interest and effort in developing ALK tyrosine kinase inhibitors (TKI). Crizotinib was the first ALK inhibitor to receive FDA approval for ALK-positive NSCLC patients treatment. However, the clinical benefit observed in targeting ALK in NSCLC is almost universally limited by the emergence of drug resistance with a median of occurrence of approximately 10 months after the initiation of therapy. Thus, to overcome crizotinib resistance, second/third-generation ALK inhibitors have been developed and received, or are close to receiving, FDA approval. However, even when treated with these new inhibitors tumors became resistant, both in vitro and in clinical settings. The elucidation of the diverse mechanisms through which resistance to ALK TKI emerges, has informed the design of novel therapeutic strategies to improve patients disease outcome. This review summarizes the currently available knowledge regarding ALK physiologic function/structure and neoplastic transforming role, as well as an update on ALK inhibitors and resistance mechanisms along with possible therapeutic strategies that may overcome the development of resistance.

Clinical data from the real world: efficacy of Crizotinib in Chinese patients with advanced ALK-rearranged non-small cell lung cancer and brain metastases

Brain metastasis in non small cell lung cancer (NSCLC) patients is often considered as a terminal stage of advanced disease. Crizotinib is a small-molecule tyrosine kinase inhibitor (TKI) for ALK-rearranged NSCLC patients. Herein, we conducted a retrospective study to explore how Crizotinib affects the control of brain metastases and the overall prognosis in advanced ALK-rearranged NSCLC patients with brain metastases in Chinese population. A total of 34 patients were enrolled, of whom 20 (58.8%) patients had baseline brain metastases before Crizotinib treatment. Among patients with brain metastases before Crizotinib, overall survival (OS) after brain metastases was significantly longer than that of patients with brain metastases after Crizotinib (median OS, not reached vs. 10.3 months, respectively, p = 0.001). There was also a significant difference in systemic progression-free survival (PFS) between patients developing brain metastases before and after Crizotinib treatment (21.2 months vs. 13.9 months, p = 0.003). In conclusion, ALK-rearranged NSCLC patients with brain metastases before Crizotinib may benefit more from Crizotinib than those developing brain metastases during Crizotinib treatment.

Clinical outcomes of advanced non-small-cell lung cancer patients with EGFR mutation, ALK rearrangement and EGFR/ALK co-alterations

The co-occurrence of epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements constitutes a rare molecular subtype of non-small-cell lung cancer (NSCLC). Herein, we assessed the clinical outcomes and incidence of acquired resistance to tyrosine kinase inhibitors (TKIs) in this subtype. So we enrolled 118 advanced NSCLC treated with TKIs. EGFR mutations and ALK rearrangements were detected by DNA sequencing or Scorpion amplification refractory mutation system and fluorescence in situ hybridization respectively. Immunohistochemistry was used to evaluate the activation of associated proteins. We found that nine in ten patients with EGFR/ALK co-alterations had good response with first-line EGFR TKI, and the objective response rate (ORR) of EGFR TKIs was 80% (8/10) for EGFR/ALK co-altered and 65.5% (55/84) for EGFR-mutant (P = 0.57), with a median progression-free survival (PFS) of 11.2 and 13.2 months, (hazard ratio [HR]=0.95, 95% [CI], 0.49-1.84, P= 0.87). ORR of crizotinib was 40% (2/5) for EGFR/ALK co-altered and 73.9% (17/23) for ALK-rearranged (P= 0.29), with a median PFS of 1.9 and 6.9 months (hazard ratio [HR], 0.40; 95% [CI] 0.15-1.10, P = 0.08). The median overall survival (OS) was 21.3, 23.7, and 18.5 months in EGFR-mutant, ALK-rearranged, and EGFR/ALK co-altered (P= 0.06), and there existed a statistically significant difference in OS between ALK-rearranged and EGFR/ALK co-altered (P=0.03). Taken together, the first-line EGFR-TKI might be the reasonable care for advanced NSCLC harbouring EGFR/ALK co-alterations, whether or nor to use sequential crizotinib should be guided by the status of ALK rearrangement and the relative level of phospho-EGFR and phospho-ALK.

Alectinib for advanced ALK-positive non-small-cell lung cancer

PURPOSE

The pharmacology, pharmacokinetics, clinical efficacy, safety and tolerability, dosage and administration, and place in therapy of alectinib for treatment of patients with non-small-cell lung cancer (NSCLC) are reviewed.

SUMMARY

In patients with NSCLC driven by mutations of ALK, the gene coding for anaplastic lymphoma kinase (ALK), treatment with the ALK inhibitor crizotinib has been found to provide median progression-free survival (PFS) of 10.9 months; however, therapeutic failures and tumor progression to brain metastases are common with crizotinib use, prompting research to find more potent and tolerable ALK inhibitors that target major oncogenic drivers of NSCLC. Alectinib is a next-generation ALK inhibitor initially approved by the Food and Drug Administration for use in patients with metastatic ALK-positive NSCLC who are intolerant of or have disease progression during crizotinib therapy. In clinical trials, alectinib was found effective for delaying disease progression and, more importantly, reducing brain metastases in patients with NSCLC who developed resistance or intolerance to previous crizotinib therapy. Published data from clinical trials indicate that the most common grade 1 and 2 adverse effects associated with alectinib use are fatigue, constipation, peripheral edema, and myalgia; the most common grade 3 or 4 reactions include increases in creatine phosphokinase, alanine aminotransferase, and aspartate aminotransferase levels.

CONCLUSION

Alectinib appears to be effective and safe for use in patients with metastatic ALK-positive NSCLC, with demonstrated superiority over crizotinib in terms of PFS rates. Research to better define ALK inhibitor resistance mechanisms and alectinib's place in therapy is ongoing.

The function and therapeutic targeting of anaplastic lymphoma kinase (ALK) in non-small cell lung cancer (NSCLC)

Lung cancer is the leading cause of death by cancer in North America. A decade ago, genomic rearrangements in the anaplastic lymphoma kinase (ALK) receptor tyrosine kinase were identified in a subset of non-small cell lung carcinoma (NSCLC) patients. Soon after, crizotinib, a small molecule ATP-competitive ALK inhibitor was proven to be more effective than chemotherapy in ALK-positive NSCLC patients. Crizotinib and two other ATP-competitive ALK inhibitors, ceritinib and alectinib, are approved for use as a first-line therapy in these patients, where ALK rearrangement is currently diagnosed by immunohistochemistry and in situ hybridization. The clinical success of these three ALK inhibitors has led to the development of next-generation ALK inhibitors with even greater potency and selectivity. However, patients inevitably develop resistance to ALK inhibitors leading to tumor relapse that commonly manifests in the form of brain metastasis. Several new approaches aim to overcome the various mechanisms of resistance that develop in ALK-positive NSCLC including the knowledge-based alternate and successive use of different ALK inhibitors, as well as combined therapies targeting ALK plus alternative signaling pathways. Key issues to resolve for the optimal implementation of established and emerging treatment modalities for ALK-rearranged NSCLC therapy include the high cost of the targeted inhibitors and the potential of exacerbated toxicities with combination therapies.

Mechanisms of receptor tyrosine kinase activation in cancer

Receptor tyrosine kinases (RTKs) play an important role in a variety of cellular processes including growth, motility, differentiation, and metabolism. As such, dysregulation of RTK signaling leads to an assortment of human diseases, most notably, cancers. Recent large-scale genomic studies have revealed the presence of various alterations in the genes encoding RTKs such as EGFR, HER2/ErbB2, and MET, amongst many others. Abnormal RTK activation in human cancers is mediated by four principal mechanisms: gain-of-function mutations, genomic amplification, chromosomal rearrangements, and / or autocrine activation. In this manuscript, we review the processes whereby RTKs are activated under normal physiological conditions and discuss several mechanisms whereby RTKs can be aberrantly activated in human cancers. Understanding of these mechanisms has important implications for selection of anti-cancer therapies.

Drug resistance in anaplastic lymphoma kinase-rearranged lung cancer

The anaplastic lymphoma kinase (ALK) gene encodes a receptor tyrosine kinase, and many kinds of ALK fusion genes have been found in a variety of carcinomas. There is almost no detectable expression of ALK in adults. However, through ALK gene rearrangement, the resultant ALK fusion protein is aberrantly overexpressed and dimerized through the oligomerization domains, such as the coiled‐coil domain, in the fusion partner that induces abnormal constitutive activation of ALK tyrosine kinase. This results in dysregulated cell proliferation. ALK gene rearrangement has been observed in 3%‐5% of non‐small‐cell lung cancers, and multiple ALK inhibitors have been developed for the treatment of ALK‐positive lung cancer. Among those inhibitors, in Japan, 3 (4 in the USA) ALK tyrosine kinase inhibitors (TKIs) have been approved and are currently used in clinics. All of the currently approved ALK‐TKIs have been shown to induce marked tumor regression in ALK‐rearranged non‐small‐cell lung cancer; however, tumors inevitably relapse because of acquired resistance within a few years. This review focuses on ALK‐TKIs, their resistance mechanisms, and the potential therapeutic strategies to overcome resistance.